That’s very cool when it happens in a block of plastic, but not very cool when it happens in the insulating material on your satellite. Deep dielectric charging can be a major problem with satellites. The worst part is that it can be difficult to diagnose why you’ve had a discharge because the electron flux that saturated your insulator could have happened long ago and the discharge could be triggered by something small.

SLAC used to give away these “beam trees” as awards as well. A technical aside: they are created when the diffuse charge deposited by the beam is discharged through a grounded point, creating a massive spark.

Back around the turn of the century (wow, that sounds weird), I was working on a software development tool for creating parallel software. At SC2000, I met some people from FermiLab that were using the software. One of them gave me a key chain that had been made like that. They didn’t have very many key chains, they gave me one since they were using software I was involved with. The guy said they would make large ones to give as awards.

I got a lot of swag that year from companies that no longer exist. I even ended up with a 144 bags of microwave popcorn from some now defunct vendor.

Varian Medical Systems had a bunch of these around their plant in Palo Alto back in 2001. I’d probably still work there if the bay area wasn’t such an expensive place to live. 23MV X-rays or 25MeV e-beams from a 6′ guide on their normal Clinac systems. They also built the guide for SLAC in 30′ sections. It was an impressive place to work and a good bunch of people.